In recent years, as a display device which is represented by a liquid crystal display, an organic electroluminescence display device (hereinafter, simply abbreviated as “organic EL display device”) using an organic electroluminescence element (hereinafter, simply abbreviated as “organic EL element”) is attracting attention. The organic EL display device is of a self-luminous type, and has a characteristic of low power consumption. It is considered that the organic EL display has sufficient responsiveness to a high-definition and high-speed video signal, and the development for practical use and commercialization are closely proceeding.
The organic EL display device has a plurality of light-emitting elements each of which includes a light-emitting unit ELP and a driving circuit for driving the light-emitting unit ELP. For example, FIG. 23A is an equivalent circuit diagram of the light-emitting element which includes the driving circuit having two transistors and one capacitive unit (for example, see JP-A-2007-310311). The driving circuit has a drive transistor TDrv which includes source/drain regions, a channel forming region, and a gate electrode, a video signal write transistor TSig which includes source/drain regions, a channel forming region, and a gate electrode, and a capacitive unit C1. Reference numeral CEL represents parasitic capacitance of the light-emitting unit ELP.
In the drive transistor TDrv, one region of the source/drain regions is connected to a current supply line CSL, and the other region of the source/drain regions is connected to the light-emitting unit ELP and also connected to one end of the capacitive unit C1 to constitute a second node ND2. The gate electrode of the drive transistor TDrv is connected to the other region of the source/drain regions of the video signal write transistor TSig and also connected to the other end of the capacitive unit C1 to constitute a first node ND1.
In the video signal write transistor TSig, one region of the source/drain regions is connected to a data line DTL, and the gate electrode is connected to a scanning line SCL.
The current supply line CSL is connected to the current supply unit 100, the data line DTL is connected to the video signal output circuit 102, and the scanning line SCL is connected to the scanning circuit 101. At the time of light emission of the light-emitting unit ELP (that is, before and after light emission of the light-emitting unit ELP), a current flows from the current supply unit 100 to the light-emitting unit ELP through the current supply line CSL and the drive transistor TDrv, and the potential of the anode electrode (corresponding to the second node ND2) of the light-emitting unit ELP rises until the operation point corresponding to the current value is reached.